Flat bed trailers are trailers which, in many instances, lack rigid or permanent side walls. Such trailers are particularly useful for larger and irregularly shaped goods which do not require complete protection from the elements. The trailers are also useful in the small yards where the trailer may be loaded or unloaded on either side thereof. Some of the trailers may have temporary protection by means of side walls which are fabricated out of a canvas or a canvas like material.
Generally, the trailers have a first load carrying portion which is at a lower height than a second load carrying portion which is located at the front (adjacent the cab) of the trailer. The raised portion is necessary to provide the structural integrity for the unit.
Naturally, the raised portion lessens the amount of space available for storage. Furthermore, it is at a height that is difficult for the driver to access.
As will be appreciated, it is also desirable to have all of the trailer at a relatively low height so that the driver can readily obtain access thereto. This also increases the load capacity since the main restriction is height which must take into account overpasses and the like. Generally, in North America, the maximum height allowed is standardized at approximately 13.5 feet.